Improvement in differential pulleys



2 Sheets--She I 1.1. FEWKES.

- Differential Pulley. r

' ntedFeb.2,1875.

QS heetr-Sheet Z. 1. r. FEWKE-S. ,Difier'ential Pulley. No. 159,400.

Patented Fe b 2,387.5.

UNITED STATES PATENT OEEIoE.

JOSEPH T. FEWKES, PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO JACOB H. ARMBRUSTER, OF SAME PLACE.

IMPROVEMENT lN DIFFERENTIAL PULLEYS.

Specification forming part of Letters Patent No. 159,400, dated February 2, 1875; application filed October 31, 1874.

To all whom it may concern:

Be it known that I, JOSEPH T. FEwKEs, of the city and county of Philadelphia, and State of Pennsylvania, have invented a new and useful lmprovementin Differential Pulleys and Hoisting Apparatus; and I do hereby declare the following to be a clear and exact description of the nature thereof, sufficient to enable others skilled in the art to which my invention appertains to fully understand, make, and use the same, reference being had to the accompanying drawings, making part of this specification, in which- Figures 1 and 3 are face views of the device embodying my invention. Fig.2 is an end view thereof. Fig. 4 is a transverse section in line a: m, Fig. 1. Fig. 5 is a similar section in line y y, Fig. 1.

Similar letters of reference indicate correspondin g parts in the several figures.

My invention consists in two pulleys adapted to move in common or separately, and thus serve the purpose of either a differential pulley or a hoisting apparatus.

The pulleys, with a spring between them, are mounted on a frame which. has a lateral extension for attachment of a convenientlyaccessible locking-piece, which bears against a sliding head mounted on the axis of the pulley, and having guiding-pins, which prevent binding of the head on the axis.

Referring to the drawings, A represents a pulley mounted on a horizontal shaft or axis, a, of a frame, B; and 0 represents a smaller pulley, which is mounted parallel with the pulleyA on the same shaft or axis a. The

inner face of one pulley is formed with a shoulder or stop, b, and the other pulley with a projection or ing, 0, the two pulleys having lateral play, and adapted to be brought together and separated from each other, so that i the lug and shoulder may be engaged and disengaged. The pulleys .are separated by the action of a spring, D, which is interposed between them, and brought together by the action of 'a wedging-key, E, which passes through an opening in a block or piece, d, at the side of the frame 13. On the axis or shaft of the pulleys there is fitted a sliding head, 13, from which projects laterally pins 6, which pass through the adjacent side piece of the frame B toward the key E, so that the latter will bear against said pins 6, a washer, f, being interposed between the key and ends of the pins, in order to cause the key to bear uniformly against said pins. G represents an endless chain, which is passed around thetwo pulleys A O, and also around a bottom or lower pulley, H, from which articles to be hoisted are suspended. The frame J of the pulley G has at its upper end a hook, K, which is so located that the chain Gr may be attached thereto, as occasion requires.

The operation is as follows: When the key E is forced down in the block d, the two pulleys are brought together and locked, and, owing to the shoulder and lug b c, said pulleys will rotate as one. By drawing the chain G, as at g, Fig. 1, the pulleys will operate after the manner of adifferential pulley, and a load or weight suspended from the frame of the pulley H will be readily raised or hoisted. When the key E is elevated in the block d, the action of the spring D will separate the pulleys and disconnect the shoulder and lug b 0. Now, attach the chain G, as at h, to the hook K of the lower frame, and draw on the chain, as at k, and the pulley H will be elevated; or, by releasing the chain from the hook K, and taking hold of the chain at two places, as at l, and drawing thereon at the two places, the pulley H will rise, and with it the weight or load.

When the pulleys have been used differentially, and the weight or load has been elevated to the determined height, the release of the key E will permit the quick descent of the pulley. This provision will also be serviceable for lowering articles more promptly than if the same was attempted when the pulleys work differentially.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. The combination, with the two pulleys A O, of the rising-and-falling locking-piece E, fitted to the extension-piece cl of the frame B, substantially as and for the purpose set forth.

2. The two pulleys A G and sliding head F, mounted on the same axis a, in combinacontact with the lock E, substantially as and tion with the lock E, having a rising-and-fallfor the purpose set forth. ing motion.

3. The two pulleys A G, in combination JOS. T. FEWKES. with the spring D between them, and with Witnesses: sliding head F, having laterally-extending JOHN A. WIEDERSHEIM,

pins 0, which project through the frame B, for ALBERT H. HOECKLEY. 

